There's mileage in doing further email address validation, perhaps. We do some already. A common one is gamil.com
instead of gmail.com
.
But, honestly, this shouldn't be a big enough problem to warrant putting more barriers in the way for your users such as fields to verify email addresses. It wasn't that long ago that we removed the field to verify the user's password.
There are still ways that people can/will make the same mistake as noted above, such as by copy/pasting.
The key thing is particularly that the email address is displayed back to the user if you have email confirmation enabled - which you should, this is why that feature exists and is enabled by default. The user can change their email address and resend the confirmation if they make a mistake.